Voc vs Vmpp Panel Voltage
ligwyd Registered Users Posts: 193 ✭✭
edited June 2020 in PV Installers Forum - NEC, Wiring, Installation #1
Voc (Open ciruit voltage)
Vmpp (Voltage at max power point)
When adding voltages to calculate max string voltage going into a charge controller, can you use Vmpp or must you use Voc at all times?
Is it safe to just add up Vmpp and X by 1.25 to account for cold and sunny days? Whats the rule of thumb?
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Generally, the MPPT mfg has a "String Sizer Tool" that your put your panel info into and the min temperature
and it will report if the proposed configuration is acceptable or if it will violate the warranty.
In a pinch, you could use this, and massage the results to your device:
it will at least give you the range of voltages to expect under worst case conditions.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
gen: http://tinyurl.com/LMR-Lister ,